Air vent blocking device



FIG. 1 is a perspective view of the air vent blocking device showing my new design;

FIG. 2 is a front plan view thereof;

FIG. 3 is a rear plan view thereof;

FIG. 4 is a side elevational view thereof; the opposite side being identical in appearance; and,

FIG. 5 is a top plan view thereof, the bottom plan view being identical in appearance. 

The ornamental design for an air vent blocking device, as shown and described. 